Warp knitting elastic fabric and method of fabricating therefore

ABSTRACT

Warp knitting fabric having a double needle overlap structure forming two loops on two adjacent needles in the same course, and loops being formed from double yarns one of which is a chemical filament yarn and the other yarn is a spandex yarn, and both of the yarns being knitted with the same lapping movement.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit from Provisional Application No. 61/930,959, filed Jan. 14, 2014, the content of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a knitted fabric, particularly to a warp knitted fabric with a double needle overlap structure and combinational yarns.

BACKGROUND OF THE INVENTION

Warp knitted fabrics have been widely used in women's underwear and close-fitting undergarment for maintaining a desirable body part profile. Presently, fabrics for such purposes are mostly warp knitted elastic fabrics with a locknit stitch structure (typically shown in FIG. 1), where the warp pile (velvet) is formed from chemical filament yarns from the front guide bar and half tricot base stitches are formed from spandex yarns from the back guide bar. The textile made this way has reasonably good elasticity and comfortable hand feel, and that is why it has dominated the elastic fabric market. Nonetheless, there are drawbacks in the textile with such stitch structure: the elasticity is not sufficiently great as desired, Although, the elasticity may be improved by using thicker polyurethane (i.e., spandex) yarns, thicker spandex yarns bring other problems such as curliness, exposure of the spandex yarn to the surface, poor color fastness, poor elastic recovery rate, and appearance of wrinkles after repeated stretches.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide an elastic warp knitted fabric which has a sufficient elasticity, special hand feel mimicking the peach skin, good resistance to snagging, wide range of density possible between 100 and 350 grams per square meter and wide range of suitable applications in the garment industry. This object is achieved by a warp knitted fabric with a double-needle overlap structure (or double loop stitch) of combined chemical filament yarns and spandex yarns, which may both be guided by a single guide bar or may be guided separately by two guide bars. In other words, the two types yarns have exactly the same lopping moment.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be made to the drawings and the following description in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a typical prior art warp knitted fabric in the prior art with a locknit stitch structure: technical face side in the right and technical back side in the left.

FIG. 2 is a stitch diagram showing the loop structure of a warp knitted fabric according to the present invention.

FIG. 3 is a lapping diagram showing the lapping movement of the yarns in the embodiment shown in FIG. 1, with both a nylon yarn and a spandex yarn on the same guide bar.

FIG. 4 shows a photographic face view of an actual sample of the elastic fabric with the stitch structure shown in FIG. 1.

FIG. 5 shows a photographic back view of the same sample in FIG. 4.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS OF THE INVENTION Warping of the Yarns (1) Warping of Chemical Filament Yarns;

Warping machine: Karl Mayer DS 21/30 NC-2, passive feeding mode.

Warping temperature: 23° C.; Warping humidity: 65%.

The process parameters should be set according to the above temperature and humidity conditions.

(2) Warping of Spandex Yarns:

Warping machine: Karl Mayer DSE-H21/30 NC-2, with positive feeding mode.

Warping temperature: 24° C.; Warping humidity: 78%.

The process parameters should be set according to the above temperature and humidity conditions.

The Knitting Process

Knitting machine: KarlMayer HKS2-3, HKS2-3E, HKS3-1, HKS4-1, RSE4-1 or any other single needle bar warp knitting machine.

Machine type region: E28-E50

Threading mode: full-threading.

Two types of yarns are used in this fabric: chemical filament and polyurethane fiber.

The warp knitting process as well as the characterizes of the fabric produced is mainly defined by the lapping moments of the guide bar. In this particular embodiment of the invention, the knitting process is conducted according to the lapping diagram shown in FIG. 3 and the corresponding stitch stricture shown in FIG. 2. As person of ordinary skill in the art would easily set up and operate the machine according the lapping diagram shown in FIG. 3, the detailed description of the knitting process is omitted herewith. As shown in FIG. 3, where each dot represents one needle and each horizontal row of dots represents a single stitch forming process, i.e. one course. Several rows of dots from bottom to top represent the succession of several stitch-forming processes or courses recording a complete repeat of the fabric structure, the guide bar (with both yarns) first swings in (through the gap between the needles) to the front of the needle, overlaps by two needle spaces to the right, swings out to the back of the needle, and then underlaps by one needle space to the right which completes the first course. Continuing to the next course, the guide bar swings in, overlaps by two needle spaces to the left, swings back, and then underlaps by one needle space to left complete the second course. These two courses constitute a complete repeat of the lapping movement.

With the above described lapping movement, due to the two needle space overlap followed by one needle space underlap (zero or two needle space underlap is also acceptable), the fabric simultaneously has floats 2 (characteristic of weft knitting) and extending underlaps 1 (characteristic of warp knitting). Also due to the two needle space overlap, the needle brings through the loop four yarns at the same time (two chemical filament yarns and two spandex yarns), resulting in an increased fiction which causes many short fine fibers appear on the surface which has the extending underlaps, which in turn creates a very pleasant hand feel. Furthermore, as each needle bringing in four yarns at the same time, it results in a higher yarn density, greater surface coverage, less prone to laddering and bursting, and a higher content of spandex (up to 40% and above) which entails higher elasticity and elastic strength. Additionally, due to the short extending underlap (no more than 2 needle spaces), it is less prone to snagging. The chemical filament yarns can be either polyester (PET) or polyamide (nylon), and are commonly available off the shelf in the market. Any fabric grades and specs are acceptable and selected according to specific applications. The section of the yarns in the practice of the present invention is within ordinary skill in the art.

Dyeing and Finishing

Dry cleaning (or washing with water)→Scheduling→Overflow dyeing→Dewatering→Finishing. These process are industry routines known to people of ordinary skill in the art.

The advantageous effects brought about by the present invention:

1. The elastic fabric of this invention has a high elastic recovery rate, usually above 90%. 2. The elastic fabric of this invention naturally has a pleasant hand feel like the peach skin even without sanding the surface. 3. The elastic fabric, as the example shown in FIG. 4 and FIG. 5, of this invention has a higher yarn density, greater surface coverage, resulting in a greater resistance to snagging. The snag-proof rate can reach 4.5.

In sum, with these desirable effects, the fabric of the present invention will find a wide range of applications in the garment industry, particular in underwear and other body-fitting clothing articles.

While there have been described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes, in the form and details of the embodiments illustrated, may be made by those skilled in the art without departing from the spirit of the invention. The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims. 

What is claimed is:
 1. A warp knitting fabric comprising a double needle overlap forming two loops on two adjacent needles in the same course, said loops being formed from double yarns one of which is a chemical filament yarn with the other being a spandex yarn, and both yarns being knitted with the same lapping movement.
 2. The warp knitting fabric of claim 1, wherein a complete repeat of said lapping movement consists of (a) swing in to the front the needle, (b) overlap two needle spaces to the right, (c) swing out to the back of the needle, (d) underlap one needle space to the right to complete a first course, (e) swing in, (f) overlaps two needle spaces to the left, (g) swing back, and (h) underlap one needle space to the left to complete a second course.
 3. The warp knitting fabric of claim 1, wherein said chemical filament yarn is nylon. 